Introduction

The Aggregator is based on and part of the Eclipse b3 project. b3 provides a versatile and adaptable framework supporting build, assembly and deployment processes. It supports a rich set of use cases. One of those - the aggregation of repositories - is the focus of the b3 Aggregator tool.

The Aggregator combines repositories from various sources into a new aggregated p2 repository. It can also be configured to produce a hybrid p2/Maven2 repository.
There are many situations where using aggregated repositories is a good solution. The reasons vary from licensing issues to organizational requirements:

Owners of a p2 repo for a given project may not be in position to host all required or recommended components due to licensing issues - Buckminster's SVN support can serve as an example here, as it requires components available through the main Eclipse p2 repo as well as third-party components. Hence users have to visit several repos for a complete install.

Projects want to provide convenient access to their products - Installation instructions requiring the user to visit several repos for a complete install are not uncommon. An aggregated repo for all those locations provides a convenient one-stop strategy. The aggregation may support mirroring all consumed p2 repos or simply providing an indirection via a composite repo.

Organizations or teams want control over internally used components - It may be necessary to have gated access to relevant p2 repos and do an organizational "healthcheck" of those before internal distribution. Furthermore, internally used aggregated repos can provide a common basis for all organizational users.

Increase repository availability - by aggregating and mirroring what is used from multiple update sites into an internally controlled server (or several).

Distributed Development Support - an overall product repository is produced by aggregating contributions from multiple teams.

The Aggregator tool is focused on supporting these specific requirements, and it plays an important role in the full scope of the b3 project. The Aggregator is however used in scenarios outside of the traditional "build domain" and this has been reflected in the user interface which does not delve into the details of "building" and should therefore be easy to use by non build experts.

Furthermore, it is worth noting that:

the Aggregator is based on EMF models

headless execution of aggregation definitions (once they have been created) is possible using a command line packaging of the Aggregator

-i org.eclipse.b3.aggregator.engine.feature.feature.group is the name of the aggregator feature

Functional Overview

The Aggregator performs aggregation and validation of repositories. The input to the aggregator engine (that tells it what to do) is a b3aggr EMF model. Such a model is most conveniently created by using the b3 Aggregator editor. This editor provides both editing and interactive execution of aggregation commands. The editor is based on a standard EMF "tree and properties view" style editor where nodes are added and removed to form a tree, and the details of nodes are edited in a separate properties view. Once a b3aggr model has been created it is possible to use the command line / headless aggregator to perform aggregation (and other related commands). (Note that since the b3aggr is "just and EMF model", it can be produced via EMF APIs, transformation tools, etc. and thus support advanced use cases).

TODO: Describe "email/blame support" (different receivers of email for different parts, supports sub-umbrella projects where something may be wrong with a combination of contributions from different teams - it is not the problem of a particular team). Support for CC, mock emails for testing vs. production runs.

Getting started with standard examples

In the following sections we provide two simple examples that are easy to replicate and should highlight the most important features of the Aggregator.
The first example deals with the creation of two variations of a p2 repo. The second shows the Aggregator's Maven support.

Aggregating a p2 repo

The first sample aggregation is build around Buckminster and its support for Subversive. The objective of this aggregated repo is to:

provide a "one-stop shop" experience

conveniently pull in third-party components that are not hosted at Eclipse

This example already includes some of the more advanced aggregation features. Stepping through the model view from the top node the following components can be identified:

The top node Aggregator groups all model definitions regarding Configurations and Contributions. Looking at the properties section at the bottom we see that:

the top node has been provided with a mandatory Label with the value "Helios + Buckminster for Subversive"; this is also the label that is shown to users when accessing the aggregated repo via the p2 update manager

the Build Root identifies the location to which the artifacts of the aggregated repo will be deployed

The aggregation is defined for three configurations (i.e. os=win32, ws=win32, arch=x86; etc)

any number of configurations can be defined

during the aggregation process all dependencies of the contributed components will be verified for all provided configurations, unless exceptions are defined (see below)

The first Contribution to the aggregation is labeled "Helios 3.5".

this contribution represents the simplest example of a contribution

one Mapped Repository is defined for this contribution (it can have multiple); all that is needed is a user-defined label and the URL of the repository that should be included

the result of this definition is that the complete Helios p2 repo will be included in the aggregated repo

The second Contribution is labeled "Subversive SVN connectors" and deals with the inclusion of bundles provided by Polarion. This contribution includes binary configuration-specific artifacts which are only available for win32. If a simple contribution would be defined the aggregation would fail for all non-win32 configurations, and hence the aggregation would fail as a whole.

this requires a definition of Valid Configurations Rules that state exceptions

the rules defined for the the three components in question essentially state that the verification process for those components should only be performed for win32-based configurations

The third Contribution is labeled "Buckminster (latest)". It shows another advanced feature - an Exclusion Rule.

remember that the objective of the sample repo is to provide convenient setup of Buckminster with Subversive support, and since Buckminster's Subclipse and Subversive support are mutually exclusive, we want to exclude the features for Subclipse from the aggregated repo to make it easier for the user.

this is done using an Exclusion Rule defined for each Installable Unit that should be excluded

A list of all included repos is displayed at the bottom of the model editor view

this list allows browsing the contents of all repos

this part of the model is not editable

The aggregation can be run by right-clicking any node in the model and selecting Build Repository.
This example was setup to use a mirroring approach for all contributed repos. Hence, the complete contents of all included can be found in the aggregated repos target location specified under Build Root.

Check the next section for a slightly different approach.

Providing a repo indirection

Mirroring all repo artifacts of your aggregated contributions is a very valuable and important feature when performing aggregation, but there are also many cases where this is not necessary. It is possible to turn off artifact mirroring/copying by changing one property for a defined contribution.
Each Mapped Repository has a boolean property called Mirror Artifacts which can be set to false in order to prevent copying all artifacts of the contributed repo to the aggregated repo.

The following buckminster_helios_redirect.b3aggr is a variation of the first example with the Mirror Artifacts property set to false for all contributed repos. Running this aggregation will result in a composite repository that provides indirection to the contributed repos.

b3 Aggregator - mirroring disabled

Creating a Maven-conformant p2 repo

A powerful feature of the Aggregator is the ability to create aggregated repos that can be consumed as Maven repos, (i.e. providing the directory/file structure and artifacts required by Maven). An aggregated repository that supports Maven can be consumed both as a p2 and a Maven repo (at the same time). This flexibility is possible thanks to p2's separation of dependency meta-data and the actual location of the referenced artifacts.

In order to create a Maven-conformant aggregate repo all that is required is to set the property Maven Result property of the Aggregator to true. The aggregation deployed to the Build Root location will be a Maven repo.

Headless support

Running from the command line

For a detailed listing of the available options consult the next section.

Command line options

Option

Value

Default

Description

--buildModel

<path to build model>

This value is required

Appoints the aggregation definition that drives the execution. The value must be a valid path to a file (absolute or relative to current directory).

--action

VERIFY

BUILD

CLEAN

CLEAN_BUILD

BUILD

Specifies the type of the execution.

VERIFY - verifies model validity and resolves dependencies; no artifacts are copied or created

BUILD - performs the aggregation and creates the aggregated repository in the target location

CLEAN - cleans all traces of previous aggregations in the specified target location

CLEAN_BUILD - performs a CLEAN followed by a BUILD

--buildId

<string>

build-<timestamp in the format yyyyMMddHHmm>

Assigns a build identifier to the aggregation. The identifier is used to identify the build in notification emails. Defaults to: build-<timestamp> where <timestamp> is formatted according as yyyyMMddHHmm, i.e. build-200911031527

--buildRoot

<path to directory>

buildRoot declared in the aggregation model

Controls the output. Defaults to the build root defined in the aggregation definition. The value must be a valid path to a directory (absolute or relative to current folder). If the desired directory structure does not exist then it is created.

--production

N/A

N/A

Indicates that the build is running in real production. That means that no mock emails will be sent. Instead, the contacts listed for each contribution will get emails when things go wrong.

CAUTION: Use this option only if you are absolutely sure that you know what you are doing, especially when using models "borrowed" from other production builds without changing the emails first.

--emailFrom

<email>

Address of build master

Becomes the sender of the emails sent from the aggregator.

--emailFromName

<name>

If --emailFrom is set then this option sets the real name of the email sender.

--mockEmailTo

<email>

no value

Becomes the receiver of the mock-emails sent from the aggregator. If not set, no mock emails are sent.

--mockEmailCC

<email>

no value

Becomes the CC receiver of the mock-emails sent from the aggregator. If not set, no mock CC address is used.

--logURL

<url>

N/A

The URL that will be pasted into the emails. Should normally point to the a public URL for output log for the aggregator so that the receiver can browse the log for details on failures.

--logLevel

DEBUG

INFO

WARNING

ERROR

INFO

Controls the verbosity of the console trace output. Defaults to global b3 settings.

The prefix to use for the subject when sending emails. Defaults to the label defined in the aggregation definition. The subject is formatted as: "[<subjectPrefix>] Failed for build <buildId>"

--smtpHost

<host name>

localhost

The SMTP host to talk to when sending emails. Defaults to "localhost".

--smtpPort

<port number>

25

The SMTP port number to use when talking to the SMTP host. Default is 25.

--packedStrategy

COPY

VERIFY

UNPACK_AS_SIBLING

UNPACK

SKIP

value from the model

Deprecated (Use only with on-the-fly transformation from deprecated build models)

Controls how mirroring is done of packed artifacts found in the source repository. Defaults to the setting in the aggregation definition.

--trustedContributions

<comma separated list>

no value

Deprecated (Use only with on-the-fly transformation from deprecated build models)

A comma separated list of contributions with repositories that will be referenced directly (through a composite repository) rather than mirrored into the final repository (even if the repository is set to mirror artifacts by default).

Hudson integration

Currently there is no support for Hudson.

Aggregator model components and specific actions

This section provides an in-depth description and reference of the Aggregator model, listing all model components, properties and available actions.

Global actions

The following aggregator-specific actions are available via the context menu that can be invoked on any node in the Aggregator model editor:

Aggregator

The root node of any aggregation model is the Aggregator node. It specifies a number of global properties including the Build Root (the target location of the aggregated repository) as well as the repo structure (maven-conformant or classic p2 setup).
There are several child components some of which can be reference in other parts of the model: Configuration, Contribution, Contact, Custom Category, Validation Repository, and Maven Mapping.

Controls the output structure of the aggregated repo. If true, the aggregated repo will be Maven-conformant. Both the structure and meta-data of the aggregated repository will follow the conventions required by Maven.

NOTE that due to the flexibility of p2 (separation of meta-data about dependencies and location of artifacts) the aggregated repo will at the same time also function as a valid p2 repository.

Packed Strategy

Copy

Verify

Unpack as Sibling

Unpack

Skip

Copy

This property controls how packed artifacts found in contributed repositories are handled when building the Aggregation:

Copy - if the source contains packed artifacts, copy and store them verbatim. No further action

Verify - same as copy but unpack the artifact and then discard the result

Unpack as Sibling - same as copy but unpack the artifact and store the result as a sibling

Unpack - use the packed artifact for data transfer but store it in unpacked form

Skip - do not consider packed artifacts. This option will require unpacked artifacts in the source

Sendmail

false

true

false

Controls whether or not emails are sent when errors are detected during the aggregation process. A value of false disables sending of emails (including mock emails).

Type

S

I

N

M

C

R

S

Indicates the Aggregation type. This is an annotation merely for the benefit of the build master. It is not visible in the resulting repo.

S - stable

I - integration

N - nightly

M - milestone

C - continuous

R - release

Configuration

An Aggregation may have one or more Configuration definitions. The aggregated repo will be verified for all added configurations. If dependencies for any of the given configurations fails the aggregation as a whole fails. It is however possible to specify exceptions for individual Contributions.

A Configuration is a combination of the following properties:

Property

Value(s)

Default Value

Comment

Architecture

X86

PPC

X86_64

IA64

-

Specifies the architecture for which this configuration should be verified.

Enabled

true

false

true

Disables (false) or enables (true) the configuration for the aggregation process.

Operating System

Win32

Linux

MacOSX

-

Specifies the operating system for which this configuration should be verified.

Window System

Win32

GTK

Carbon

cocoa

-

Specifies the windowing system for which this configuration should be verified.

Contribution

Contributions are the key element of any aggregation. Contributions specify which repositories (or parts thereof (category, feature, product, IU)) to include, and the constraints controlling their inclusion in the aggregated repository.
A contribution definition may consist of several Mapped Repository and Maven Mapping components.

A prefix added to the label of this repository when displayed in the p2 update manager. In the absence of custom categories this allows a useful grouping of repositories in an aggregated repository to be specified.

Description

<string>

-

Description of the Mapped Repository. For documentation purposes only.

Enabled

true

false

true

Controls whether a Mapped Repository is considered as part of the Contribution. Setting this property to false excludes the repository from the verification and aggregation process.

Location

<URL>

This (required property) specifies the location of the repository that should be added to the enclosing Contribution.

Mirror Artifacts

true

false

true

Controls whether the contents (artifacts) of the specified repository will be copied to the target location of the aggregated repository.

Nature

<nature>

p2

This specifies the nature of the repository, i.e. which loader should be used for loading the repository. The number of available repository loaders depends on installed extensions. By default, p2 and maven2 loaders are present in the installation.

Product

Defining Product components allows the addition of individual Eclipse products to the aggregation to be specified (as opposed to mapping the complete contents of a given Mapped Repository. This naturally requires that products are present in the repositories being mapped.

Property

Value(s)

Default Value

Comment

Description

<description>

-

Optional description of the mapping.

Enabled

true

false

true

Controls whether a Product is considered as part of the Contribution. Setting this property to false excludes the product from the verification and aggregation process.

Name

<product IU's id>

-

The id of the product to be included in the aggregation. A drop-down of available names is provided.

References to zero or more configurations for which the referenced bundle has to be verified. If no references are given the bundle has to be verified for all Configurations defined for the aggregation.

Version Range

<version range>

0.0.0

A version range that specifies acceptable versions for this installable unit. A pop-up editor is available.

Feature

Defining Feature components allows the addition of individual Eclipse features to the aggregation to be specified (rather than the complete contents of a given Mapped Repository). The features to include must be present in the mapped repository.

Furthermore, this component provides the means to group features implicitly into Custom Categories.

Optionally references the Custom Category definitions into which the feature should be placed upon aggregation. The relationship to the custom category is bi-directional so adding the feature to a custom category will update this property automatically in the Custom Category definition, and vice versa.

Description

<description>

no value

Optional description of the mapping.

Enabled

true

false

true

Controls whether a referenced feature is considered as part of the Contribution. Setting this property to false excludes the feature from the verification and aggregation process.

Name

<product IU's id>

-

The id of the feature to be included in the aggregation. A drop-down of available names is provided. ERROR . should probably be Feature IU's id

References to zero or more configurations for which the referenced feature should be verified. If no references are given the feature is verified for all Configurations defined for the aggregation.

Version Range

<version range>

0.0.0

A version range that specifies acceptable versions for this installable unit. A pop-up editor is available.

Exclusion Rule

The Exclusion Rules provides an alternative way to control the content of the aggregated repository. An exclusion rule may specify exclusion of any bundle, feature or product. The excluded IU will not be considered in the aggregation and verification process. Each exclusion rule can only reference one IU id.

Property

Value(s)

Default Value

Comment

Description

<string>

-

Description for documentation purposes.

Name

<product IU's id>

-

The id of the installable unit to be excluded from the aggregation. A drop-down of available names is provided. ERROR - product IU should be just IU id

Version Range

<version range>

0.0.0

A version range that specifies versions of this IU to be excluded. A pop-up editor is available.

Valid Configuration Rule

By default all contributed contents of a Mapped Repository will be verified for all Configurations defined for the aggregation. A Valid Configuration Rule provides more control over validation. When using a Valid Configuration Rule, the referenced IUs (product, feature, or bundle) will only be verified and aggregated for the configurations specified in the rule. The rule only applies if the whole repository is mapped (i.e. when no explicit features, products, bundles or categories are mapped, regardless if they are enabled or disabled).

Property

Value(s)

Default Value

Comment

Description

<string>

-

Description for documentation purposes.

Name

<IU id>

-

The id of the IU to be included in the verification process. A drop-down of available names is provided.

References to one or more configurations for which the referenced IU should be verified. This implicitly excludes verification and aggregation for all other Configurations defined as part of the aggregation model.

Version Range

<version range>

0.0.0

A version range that specifies versions of this installable unit for which the rule should apply. A pop-up editor is available.

Maven Mapping (Contribution)

Contact

Defines a resuseable contact element which can be referenced in other parts of the model and may be used to send notifications about the aggregation process.

Property

Value(s)

Default Value

Comment

Email

<email>

-

The email to be used when notifying the contact.

Name

<string>

-

Full name of the contact. May be displayed as label when referenced in other parts of the model.

Custom Category

A Custom Category provides a grouping mechanism for features in the aggregated repository. A custom category can be referenced by Features defined for inclusion from a Mapped Repository.
The relationship to between Custom Category and a Feature is bi-directional. Thus, adding the feature to a custom category will update this property automatically in the Feature definition, and vice versa.

Property

Value(s)

Default Value

Comment

Description

<string>

-

Description of the category as displayed when accessing the aggregated repository.

Label displayed for the category when accessing the aggregated repository via the p2 update manager.

Validation Repository

A Validation Repository is used to define that a repository should be used when validating dependencies for the aggregation but whose contents should not be included in the aggregated repository.
It supports the cases where the objective is to create a repository that is not self sufficient, but rather a complement to something else (typical use case is an aggregation of everything produced by an organization with validation against the main Eclipse repository).

Property

Value(s)

Default Value

Comment

Enabled

true

false

true

Controls whether a Validation Repository is considered during the verification and aggregation process. Setting this property to false excludes the repository from the verification and aggregation process.

Location

<URL>

Specifies the location of the repository.

Nature

<nature>

p2

This specifies the nature of the repository, i.e. which loader should be used for loading the repository. The number of available repository loaders depends on installed extensions. By default, p2 and maven2 loaders are present in the installation.

Maven Mapping

The Aggregator supports the creation of Maven-conformant repositories. A Maven repository requires a structure and use of naming conventions that may have to be achieved by a transformation of the Bundle-SymbolicName (BSN) when working with Eclipse bundles. There is a default translation from BSN naming standard to Maven. If that is not satisfactory,
custom transformations are supported by the definition of one or more Maven Mappings which can be defined at the Aggregator and the Contribution level.

This only applies when the Maven Result property of the Aggregator model is set to true. In that case all defined Maven Mappings are applied in the order in which they appear in the model starting from the most specific to the most generic. That means for each artifact that a Contribution adds to the aggregated repository:

first Maven Mappings defined as children of a Contribution are applied in the order in which they appear as children of the parent Contribution node

second Maven Mappings defined as children of the Aggregator model are applied in the order in which they appear as children of the parent Aggregator node

finally the default Maven Mapping is applied

The most generic mapping is a default pattern that is applied whenever a Maven result should be created. It does not need to be added explicitly to the model.
A mapping is specified by a regular expression (applied to each BSN) and two replacements (one for groupId, another one for artifactId) which refer to the resulting Maven repo structure. The default pattern is:

^([^.]+(?:\.[^.]+(?:\.[^.]+)?)?)(?:\.[^.]+)*$

The default maven mapping defines as replacements $1 for groupId and $0 for artifactId. Hence, when applying the mapping to a BSN up to 3 segments (with dots as segment delimiters) are considered as the group, and the whole BSN is considered as the artifact name. If this is a applied to something like org.eclipse.b3.aggregator the groupId would be org.eclipse.b3 and the artifactId org.eclipse.b3.aggregator. The resulting Maven repo would have the folder structure: